Another failure of peer review, due to corrupt temperature data from a single station

UPDATED – see note below. This appeared in Eurekalert a couple of weeks ago. The headline, at first glance, looks like good news, right? “Global warming” is killing off tsetse flies, what’s not to like? Read on, because a photo really is worth a thousand words.


Zambezi Valley may soon be too hot for tsetse flies

Tsetse are blood-feeding insects that transmit trypanosome pathogens which cause sleeping sickness in humans across sub-Saharan Africa; without treatment, the disease is fatal. Photo: Judy Gallagher CC BY 2.0

From STELLENBOSCH UNIVERSITY via Eurekalert

A new study, based on 27 years of data from Mana Pools National Park in Zimbabwe, suggests that temperature increases over the last three decades have already caused major declines in local populations of tsetse flies.

This analysis, published in the journal PLOS Medicine this week, provides a first step in linking temperature to the risk of sleeping sickness in Africa.

Tsetse are blood-feeding insects that transmit trypanosome pathogens which cause sleeping sickness in humans across sub-Saharan Africa. Without treatment, the disease is fatal. Parasites of this genus also cause nagana, animal African trypanosomiasis (AAT), in livestock. The most recent global estimates indicate that AAT kills approximately one million cattle per year.

The study is based on prolonged laboratory and field measures of fly densities from the 1990s, and nearly continuous records of climatic data since 1975, recorded by researchers based at the Rekomitjie Research Station in the park. Since the 1990s, catches of tsetse flies from cattle in the park declined from more than 50 flies per animal per catching session in 1990, to less than 1 fly per 10 catching sessions in 2017. Since 1975, mean daily temperatures have risen by nearly 1° C and by around 2° C in the hottest month of November.

Researchers from the Liverpool School of Tropical Medicine (LSTM), the South African Centre of Excellence for Epidemiological Modelling and Analysis (SACEMA) at Stellenbosch University, and the Natural Resources Institute at the University of Greenwich, developed a mathematical model, which showed that recent increases in temperature could account for the simultaneous decline of tsetse. The results provided evidence that locations such as the Zambezi Valley in Zimbabwe may soon be too hot to support tsetse populations.

“If the effect at Mana Pools extends across the whole of the Zambezi Valley, then transmission of trypanosomes is likely to have been greatly reduced in this warm low-lying region”, says Dr Jennifer Lord, lead author and postdoctoral fellow at LSTM.

While this would be good news for the disease situation in Zambezi Valley, rising temperatures may have made some higher, cooler parts of Zimbabwe, more suitable for the flies.

Professor John Hargrove, Senior Research Fellow at SACEMA, says the effect of recent and future climate change on the distribution of tsetse flies and other vectors, particularly mosquitoes, is poorly understood: “We don’t know, for example, whether the resurgence of malaria in the East African highlands in the 1990s was caused by rising temperatures or by increasing levels of drug resistance and decreasing control efforts.

“In general, the ways in which climate change will affect the spread of infectious diseases in sub-Saharan Africa is poorly understood because of sparse empirical evidence,” he adds.

However, work on tsetse and trypanosomiasis carried out at Rekomitjie over the past 59 years has produced long-term datasets for both vector abundance and climate change. The research station is located inside a protected area and has been free of agricultural activities since 1958. In 1984, the area was designated a UNESCO World Heritage Site. As not much has changed other than climate, the data from the site provided the ideal opportunity to develop a temperature-driven model for tsetse population dynamics.

Unlike mammals and birds, insects such as tsetse flies cannot regulate their own body temperatures, and their development and mortality rates are therefore strongly influenced by environmental temperatures. Pupae cannot survive at sustained temperatures below 16 or above 32° C. In addition, tsetse populations can become established in an area only if there are sufficient numbers of host animals and suitable vegetation to support tsetse, Prof. Hargrove explains.

He warns, however, that the Hwange National Park in Zimbabwe and Kruger National Park in South Africa are examples of areas where suitable hosts and habitat for tsetse are abundant. “Tsetse flies did occur in these areas in the 19th century, but they were always marginal because the winters there were rather too cold. With the massive rinderpest outbreak of the middle 1890s, when the vast majority of ungulates died, tsetse disappeared from these areas and have never established themselves again. But if temperatures continue to increase there is a danger that they may re-emerge.”

While tsetse-borne disease holds no danger for wildlife, as they have adapted to each other over millennia, control measures might have to be adopted in case tsetse re-occupy these parks and threaten cattle and humans nearby. According to Prof. Hargrove prophylactic drugs can protect livestock from the tsetse, but no such drugs are available for humans. The only sure way of protecting both livestock and humans is to attack the fly.

The paper:

Climate change and African trypanosomiasis vector populations in Zimbabwe’s Zambezi Valley: A mathematical modelling study

Jennifer S. Lord, John W. Hargrove, Stephen J. Torr, Glyn A. Vale

https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002675

Abstract

Background

Quantifying the effects of climate change on the entomological and epidemiological components of vector-borne diseases is an essential part of climate change research, but evidence for such effects remains scant, and predictions rely largely on extrapolation of statistical correlations. We aimed to develop a mechanistic model to test whether recent increases in temperature in the Mana Pools National Park of the Zambezi Valley of Zimbabwe could account for the simultaneous decline of tsetse flies, the vectors of human and animal trypanosomiasis.

Methods and findings

The model we developed incorporates the effects of temperature on mortality, larviposition, and emergence rates and is fitted to a 27-year time series of tsetse caught from cattle. These catches declined from an average of c. 50 flies per animal per afternoon in 1990 to c. 0.1 in 2017. Since 1975, mean daily temperatures have risen by c. 0.9°C and temperatures in the hottest month of November by c. 2°C. Although our model provided a good fit to the data, it cannot predict whether or when extinction will occur.

Conclusions

The model suggests that the increase in temperature may explain the observed collapse in tsetse abundance and provides a first step in linking temperature to trypanosomiasis risk. If the effect at Mana Pools extends across the whole of the Zambezi Valley, then transmission of trypanosomes is likely to have been greatly reduced in this warm low-lying region. Conversely, rising temperatures may have made some higher, cooler, parts of Zimbabwe more suitable for tsetse and led to the emergence of new disease foci.


My analysis

A model for fly population mortality is only as good as the temperature data used to run the model. It appears they only used one source of temperature data, the only one available to them, the Rekomitjie Research Station.

Interestingly, this helpful photo was also included in the press release from Eurekalert. It is the weather station used to monitor climate at the Rekomitjie Research Station, Zimbabwe. I provide it below, click for full-size.

Work on tsetse and trypanosomiasis carried out at the Rekomitjie Research Station in Zimbabwe over the past 59 years has produced long-term data sets for both vector abundance and climate change. The research station is located inside a protected area and has been free of agricultural activities since 1958. In 1984, the area was designated a UNESCO World Heritage Site. CREDIT Jennifer Lord

At the scale displayed above, you might not notice some important details about the weather station itself, but I did. Here it is, magnified:

Climate monitoring weather station at Rekomitjie Research Station, Zimbabwe. Magnified 2.5x

Notice anything odd? I sure did. As many of you know, I’ve spent years looking at weather stations around the world, spotting problems that contribute to temperature bias. This one has at least four visible biases that will likely cause it to read warmer than it should, especially in the overnight Tmin temperature.

Here are the issues:

  1. Metal roof is nonstandard. It looks like they used the same sheet roof as the buildings in the background.Stevenson Screens are defined to have a wooden roof, painted white. I would expect this metal roof to bias the Tmax upwards in days with direct sun.
  2. Closer to surface than normal. While I can’t absolutely confirm this with a measurement, it appears the based of the Stevenson screen is about 1 meter from the surface, based on my experience with inspecting weather stations.  The standard is supposed to be a minimum of 1.5 meters. This will bias both the Tmax and Tmin upwards if my observation is correct.
  3. Cattle guard surrounding station. This metal structure will act like a heat sink, biasing the Tmin temperature upwards as it dumps the heat it has absorbed from the sun during the day.

We don’t know when these changes occurred in the record, but it is clear to me that combined, these three observed issues at the Rekomitjie Research Station will likely contribute an upward bias effect on temperatures measured by this station.

4. But wait, there’s more.

The view of the station from Google Earth also tells a story. about upwards temperature bias. It is well-known that when a weather station does not have unobstructed air flow around it, it will contribute to upwardly biased Tmin temperatures at night. It is also known that trees around the weather station prevents some Long Wave IR from the earth warmed during the day by the sun from being sent into the upper atmosphere, being reflected back to the ground by tree leaves. This keeps the air near the ground warmer.

As we see in the Google Earth photo below, the weather station is surrounded by trees and structures, in addition to the cattle guard. Below is an aerial view with 100 meter, 30 meter, and 10 meter distance rings plotted, to be compatible with findings for temperature biases in Leroy 2010 1, which is a siting standard accepted by the World Meteorological Organization (WMO):

As you can see, there are quite a few obstructions within the 100 meter circle (the largest red one) and several  within the 30 meter circle the smaller red one. The cattle guard is within the ten meter circle, and from the photo, looks to be less than 3 meters (~10 feet) from the Stevenson Screen. Per the specifications in Leroy 2010, that would make this station a Class 5, with up to 5°C uncertainty in the temperatures it records:

Here is what the  Rekomitjie Research Station temperature plot looks like, from the paper, figure1:

Fig 1. Temperature at Rekomitjie.
(a) Monthly mean temperatures. Horizontal line at 30°C highlights the increase in the number of consecutive years during the hot-dry seasons in which mean monthly temperatures have exceeded this level. (b) Five-year running mean monthly temperature (°C) anomalies relative to 1960–1990 reference period.

As you can see in Figure1 from the Lord et al. paper2 , the span of temperature anomaly from 1965 to present is about 1.5°C, which is still smaller than the uncertainty of a Class 4 station at 2°C, or considering the cattle guard, making it a Class 5 station, an uncertainty of 5°C.

Due to the siting problems, the uncertainty swamps the signal, no matter how you look at it, rendering the claims made from the data to be meaningless.

I don’t particularly blame the authors or the reviewers for not noticing this problem, because they aren’t climatologists or meteorologists they are doctors and entomologists, who wouldn’t even know to look for these sorts of problems.

However, I can blame them for this, from their own press release:

The study is based on prolonged laboratory and field measures of fly densities from the 1990s, and nearly continuous records of climatic data since 1975, recorded by researchers based at the Rekomitjie Research Station in the park. Since the 1990s, catches of tsetse flies from cattle in the park declined from more than 50 flies per animal per catching session in 1990, to less than 1 fly per 10 catching sessions in 2017. Since 1975, mean daily temperatures have risen by nearly 1° C and by around 2° C in the hottest month of November.

All well and good, assuming they actually had good climate data (they don’t), but then there’s this from A Brief History of Tsetse Control Methods in Zimbabwe and Possible Effects of Climate Change on Their Distribution

Bold mine

Odor Baited and Insecticide Treated Targets
It has been shown that the low reproductive rates of tsetse mean that the kill rate needs only to be relatively low in order to have a major control effect (Hargrove, Torr, & Kindness, 2003 4).

….

The application of insecticides directly to cattle was re-instated in the 1980s and 1990s. While the technique had been used since the 1940s, improvements in chemicals and application techniques, as well as improved understanding of fly behavior, have seen this approach yield impressive results (Hargrove et al., 2012; Torr et al., 2011; Torr et al., 2007; Hargrove et al., 2003).

The insecticide can be either be applied as a dip spray or as a pour-on formulation. The pour-on approach, applied monthly, is less error prone, and has been proven more flexible and adaptable in more remote regions, while allowing herders to adapt the approach as necessary (Swallow et al., 1995). However, this pour on method is relatively costly. The lower cost of the dip spray, and the ability to combine it with tick control, makes this a very cost-effective measure to curb AAT (Chadenga, 1992).

Despite these various control measures, neither tsetse nor trypanosomiasis have been eradicated in northern Zimbabwe. Recently, there was a spate of new cases of HAT in northern Zimbabwe, and a number of new programs and initiatives are underway to address this issue (Scoones, 2016). With the radical changes in rural livelihoods and settlement patterns that have occurred in Zimbabwe since the start of the fast-track land reform program in 2000, “it is still unclear how the reconfigured land use and occupation structures have changed exposures to trypanosomiasis” (Dzingirai et al., 2013). In addition, the potential long-term affects of climate change have also been unclear. Changes in climate could dramatically impact the fly belts, either enlarging or reducing them, depending on the changes that take place, and how these affect tsetse population growth rates and habitations.

With such low kill rates by insecticides having a “major control effect”, and the costs of insecticide control steadily decreasing with “impressive results* (Hargrove et al., 2012 5; Torr et al., 2011; Torr et al., 2007; Hargrove et al., 2003 4), one wonders if the reduction is Tsetse flies has any connection to “climate change” at all.

If it were me, I’d be withdrawing this paper as being unsupportable by the uncertain temperature data alone. I think they set out to show “climate change” was a factor, but didn’t bother to really look at the data uncertainty, nor the true impact of control measures.


UPDATE: As pointed out in comments, I missed something important in my initial review. Note this:

It has been free of agricultural settlement since 1958, when the people living there were relocated [22]. Since then, the combined area has been protected against settlement, agriculture, and illegal hunting and logging and was designated a UNESCO World Heritage Site in 1984. In this area, HAT occurs, and tsetse populations have not been exposed to any form of control.

So there’s no insecticide treatment involved, at least not inside the park. There’s also this:

Sampling of tsetse at Rekomitjie, in pursuit of various ecological and behavioural studies, has suggested a decline in tsetse abundance in the last two decades. It is difficult to interpret the catches confidently because they have been made using widely different methods at irregular intervals. From 1966, however, fed female Gpallidipes have been collected from stationary oxen at Rekomitjie, with the sole original aim of providing test insects for bioassays [3136]. Because these collections were made using a single sampling system, run at approximately the same time each day, the change in the numbers collected offer an indication of the extent of the decline in tsetse abundance over recent decades.

Catches were made for 3 hours in the afternoon during the period of peak tsetse activity [42]. Each collection team comprised two hand net catchers and an ox, operating within 2 km of the research station. Each team operated at least 200 m from other teams, in areas chosen to maximise catches in accord with seasonal changes in the distribution of tsetse between vegetation types [43]. In the 1960s, it was usual for each team to take enough tubes to collect a maximum of about 50 flies each day. This quota was set in consideration of the minimum expected catch at that time and has been maintained at this level ever since, even though it has proved impossible to meet the quota in the last two decades. Daily records are available from 1990 for the number of catching teams employed, and for the catch of each team. The monthly averages of the number of flies caught per team per day are taken as indices of fly abundance. Prior to 1990, tsetse catches regularly reached the upper limit of 50 flies; thereafter, this hardly ever occurred. Fitting the model only to catch data for the period after 1990 ensured that there was no truncation of data used in the fitting procedure.

They cite a reference [42] A diurnal and seasonal study of the feeding activity of Glossina pallidipes Aust.

which says:

In a continuation of studies of diurnal and seasonal feeding activity of Glossina pallidipes Aust. in thick riverine vegetation at Rekomitjie, in the Zambezi Valley, Southern Rhodesia, flies attracted to a stationary black ox were allowed to become engorged, then caught, marked and released.

From comparison of catches off a moving and a stationary ox, two stationary oxen standing together, and two standing out of sight of one another, in each case one being red and the other black, it appears that colour of the bait-animal is not of great importance as an attractant to G. pallidipes unless a definite choice is presented, when flies show preference for feeding on a dark surface.

So, they have a stationary “test oxen” they presumably tie up somewhere, and a pair of oxen for a color test. This seems to me to be a ridiculous sampling method, because in the actual farming situation there in Zimbabwe, cattle would be in groups, free roaming around, and foraging. They’d be rubbing into bushes and trees in the process. From the Rory Pilossof paper3, we learn this about the behavior of Tsetse flies:

Ground-spraying worked on the basis that tsetse flies spend much of their life “resting in cool, shady places provided by trees [and] holes … and directing a persistent insecticide at these sites should achieve a good control measure”.

So, with flies spending much of their lives ““resting in cool, shady places provided by trees [and] holes…” and with a “stationary ox” and a pair of oxen providing the only sustenance for blood sucking flies, you can see that it’s no wonder their catch rate has diminished so dramatically. The cattle is mostly gone from the test area, and the test animals with “catch teams” don’t likely even get to roam around where it can brush up against or take sun and heat shelter near trees and holes the flies frequent. Then one wonders if the “catch team” isn’t doing the work while wearing insecticide themselves to keep from being bitten. Did they wear the same color clothing for years to prevent the flies from being given a choice of a light and dark surface? It would seem the catch teams provide a potential bias themselves. And where are the control oxen that aren’t with catch teams?

The authors of this paper haven’t gathered any of their own data, but instead rely entire on single station weather data and fly catch data gathered by others, with no obvious control group for fly catch or weather data..

This paper is even more ridiculous than I had originally thought.

In my opinion, the lack of cattle hosts in the park and the fly capture method itself is the reason for the decline in flies, not climate change. Flies don’t thrive without cattle, and cattle don’t get bitten as much when they are led around by “catch teams” who would likely by human nature not want to get bitten. Even if the temperature data wasn’t suspect, correlation isn’t causation here.


References: 

  1. Leroy, M., 2010: Siting Classification for Surface Observing Stations on Land, Climate, and Upper-air Observations JMA/WMO Workshop on Quality Management in Surface, Tokyo, Japan 27-30 July 2010 http://www.jma.go.jp/jma/en/Activities/qmws_2010/CountryReport/CS202_Leroy.pdf
  2. Jennifer S. Lord et al., Climate change and African trypanosomiasis vector populations in Zimbabwe’s Zambezi Valley: A mathematical modelling study https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002675
  3. Rory Pilossof A Brief History of Tsetse Control Methods in Zimbabwe and Possible Effects of Climate Change on Their Distribution International Journal of African Development v.4 n.1 Fall 2016 https://scholarworks.wmich.edu/cgi/viewcontent.cgi?article=1089&context=ijad
  4. Hargrove, Torr, & Kindness, 2003  Insecticide-treated cattle against tsetse
    (Diptera: Glossinidae): What governs success? Bulletin of Entomological Research,
    93(3), 203-217.
  5. Hargrove, J. W., Ouifki, R., Kajunguri, D., Vale, G. A. & Torr, S. J. (2012). Modeling the
    control of trypanosomiasis using trypanocides or insecticide-treated livestock. PLoS
    Neglected Tropical Diseases, 6(5).

 

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56 thoughts on “Another failure of peer review, due to corrupt temperature data from a single station

  1. “Since the 1990s, catches of tsetse flies from cattle in the park declined from more than 50 flies per animal per catching session in 1990, to less than 1 fly per 10 catching sessions in 2017.” ….
    “The research station is located inside a protected area and has been free of agricultural activities since 1958.”

    The words “park” and “protected” suggest that no changes other than Mother Nature take place. Why is cattle present in the protected park area?

  2. My wife and her two kids are from Zimbabwe and sleeping is a very prevalent activity, especially the kids when the wi-fi is unavailable. Not sure if they were bitten by the bug or just lazy.

  3. Thank you.
    I added it to my list of climate impacts research – a wild and crazy field of research.

    The huge publication opportunity for anything that has to do with climate has cultivated the weirdness that everything has to do with climate and even when the researcher does not find the changes he was looking for he can still publish a climate paper because it COULD happen in the future if climate action is not taken. Those papers also get published. If you look through this list you will be amazed by the content.
    https://tambonthongchai.com/2018/06/21/climate-change-impacts1/

  4. I always thought that CAGW theory dictated that there would be little warming at the equator and the warming would be greatest at the poles. The Zambezi Valley is in the tropics so I was surprised to see a 1°C rise since the 1960s.

    While I was googling for information to support the above observation, this little gem from Prof. Thayer H. Watkins popped up.

    The climate models have some successes but they are not hard science and they are not “ready for prime time.” Human civilization would be greatly served if the climate modelers had the intellectual integrity to stop making sensationalistic predictions for the 11 o’clock news and admit much work must be done before the model projections are relevant for policy decisions.

    Dr. Watkins refers to a paper “Observational Surface Temperature Records versus Model Prediction” by Robert C. Balling, Jr. which is published in Shattered Consensus: The True State of Global Warming. That in turn led me to the work of Patrick Michaels I’ve gone down a bit of a rabbit hole 🙂

    • Prof. Thayer said it eloquently. How far down the slope of stupidity will climate “scientists” let the reputation of “science” slide. Irreparable harm is being done to the reputation of scientists worldwide, but damn it the lies must go on.
      I especially love when the have a “walk for science”, which should be read as a “walk for more government funding”. All this greatly lowers the esteem I once had for scientists.
      I’m constantly appalled that few are standing up to the BS the way Prof. Thayer is!

  5. Just the claim that a 1C increase is enough to drop the fly catch rate from 50 per animal to less than 1 per 10 animals doesn’t pass the laugh test.

    A definite case of failing to check your assumptions at the door.

    • Mark,
      See the remark that Antony highlighted
      “it has been shown that the low reproductive rates of tsetse mean that the kill rate needs only to be relatively low in order to have a major control effect” Which applies equally well to the increased
      mortality of the Tsetse flies as it does to other factors. So an small change in mortality rates over the
      15 years of the study (from 1990 to 2005) could well explain the large drop in numbers.

      • If such a tiny temperature change was sufficient to nearly wipe out the fly, the fly would have died out completely millions of years ago.

        That’s why the assumption is so ridiculous. Though I’m not surprised that you try to defend it.

  6. Yup, an oiler /w insecticide for the cows to rub on would be a more likely explanation of a 500 to 1 bug reduction than a few days being a degree warmer.

    • You need to read the article. There are no cows in the surrounding area — as the article states:
      ” It has been free of agricultural settlement since 1958, when the people living there were relocated [22]. Since then, the combined area has been protected against settlement, agriculture, and illegal hunting and logging and was designated a UNESCO World Heritage Site in 1984. In this area, HAT occurs, and tsetse populations have not been exposed to any form of control.”

      • How to explain this then…”Since the 1990s, catches of tsetse flies from cattle in the park declined from more than 50 flies per animal per catching session in 1990, to less than 1 fly per 10 catching sessions in 2017.”

        • Greg,
          Again you need to read the paper. They catch the flies by leading an oxen around the site once per day and seeing how many flies land on it.

    • You need to read the article. The site was chosen because there are no cows there and it has
      been “free of agricultural settlement since 1958, when the people living there were relocated [22]. Since then, the combined area has been protected against settlement, agriculture, and illegal hunting and logging and was designated a UNESCO World Heritage Site in 1984. In this area, HAT occurs, and tsetse populations have not been exposed to any form of control.”

      Hence the reduction in Tsetse fly numbers is not due to insecticide use changes.

      • Any chance of fly behavior changes over the decades when no cows have been allowed there? Quickly reproducing species can exhibit change pretty quickly. Which means their behavior has changed away from using cows.

  7. I could be generous and suggest this was just an accident or incompetence in the design but it is far more likely that was deliberate.

  8. I think that hard-packed ground around the Stevenson screen may introduce another upward bias in the recorded temperatures.

    • Not only that but any vehicle passing would peak the temperature again.
      They would actually be measuring a proxy for increased traffic movement.
      Its next to a road.
      The buildings in the near background are painted in an acrylic brilliant white,
      probably an outdoor with a guarantee of ten years.
      This would cool the buildings and heat the thermometer.

      The fly itself may be controllable by releasing sterile males or using efficient insecticides such as isoxazolenes.
      These are being trialled in Africa to reduce malarial vector populations.

      the class of isoxazoline-substituted benzamide derivatives. Fluralaner is an inhibitor of the arthropod nervous system. The mode of action of fluralaner is the antagonism of the ligand-gated chloride channels (gamma-aminobutyric acid (GABA)-receptor and glutamate-receptor).

      Off topic, if this site were extrapolated across the region by homogenisation, there would be a strong\
      spurious warming signal created.

      • Tsetse flies are controlled in other places simply be catching them. They are suckers for urine and use that to locate animals. If enough are caught, the population crashes.

        Tsetse flies cannot travel more than about 50m in direct sunlight. The great grazing plains used to be treeless because of elephants and grazing pressure. After the Rinderpest outbreak in 1895-1898 the number of cattle and other animals crashed so far that the thorn trees were able to get a foothold which permitted the flies to move across huge areas, tree to tree.

        Reestablishing the original flora naturally restricts the range of the flies because they get sunburned easily.

  9. Too bad you never published your data, or any paper establishing microsite bias.

    Psst. The bias for CRN 5 is about .1C ( LeRoy)

    • It’s too bad you enabled Muller to break a promise and screw me over when I provided it the first time.

      I won’t make the same mistake again twice with you. I went into this with the idea of “open access” and when I gave the early, incomplete, data to Richard Muller at BEST, at your behest, and he agreed to use it ONLY for publication, two weeks later, he was parading it in front of Congress. He lied, he broke a promise. You blew my trust, because you were the enabler via our personal relationship.

      Still working on it. Yes I know, you think it’s taking too long, but I don’t care Doing it on shoestring with volunteer time from a prominent scientist on the other side of the aisle, he wants it right, and I only get him a few hours at a time. You’ll get the final data when everyone else does, and not before.

      In the meantime, quit being a condescending jerk about it.

      • Mosh, you really deserve that reprimand because I have never seen your apology for what you did. If you did apologize, please provide a link to it so I can convince myself I am mistaken about you. Trust is earned, not granted. Betrayal of trust requires double-duty contrition and restitution.

  10. Such rigorous research (sarc), carried out by people sitting in their university armchairs at least 5000 miles from the area being “researched” is a joke. Here they are claiming that a pest – which only affects humans & cattle – has been dramatically reduced in numbers by climate change alone, without ensuring that changes to the way humans are managing their cattle have not been the cause.

    Their wild assumptions should mean they lose their sinecures, but they will probably earn a PhD or professorship, instead.

    • Ray,
      Perhaps you should read the article before making comments. The study is based on
      records of the number of flies being caught on a daily basis by researchers over a long period
      of time. Furthermore the site is situated in an area without any human agriculture or cattle. The
      paper states for instance that
      “an aerial survey for elephant and buffalo in 2014 [24] indicated that, in the 200 km2 around Rekomitjie, there was an average of 1.6 elephants and 7.3 buffalo per km2. Vale and colleagues [25] showed that c. 2 elephants per km2 can provide about half of the diet of savanna species of tsetse and can support a population of flies even when alternative hosts are heavily depleted.”

  11. Is there, somewhere, a “perfect” Stevenson screen?
    What would be a “perfect” Stevenson screen?
    A “perfect” one from birth to now.

  12. “that would make this station a Class 5, with up to 5̊C uncertainty in the temperatures it records”

    Does this mean the uncertainty is +/– 5°C or +/- 2.5°C?

    While the uncertainty may be high, and thus the accuracy low, does that same uncertainty apply to a trend? Always, of course, assuming that confounding conditions are not changing and the instruments are not changing, if there is a slow movement in one direction over an extended enough time period,
    is it still most reasonable to believe the trend is probably just noise within the basic +/- uncertainty of the measurements?

    That is to say, is it just as probable that a long term trend upward totaling 1.5°C is just as likely to actually be a trend downward or no trend of all?

    Still, the apparent fact that the cattle being investigated may be among those treated to repel the flies makes the whole thing useless from a ‘climate change’ perspective unless the researchers can show that there was adequate controls for the treatment factor. As is, they would have a much better paper just on the effectiveness, or not, of treating the cattle — except that possible temperature changes would be a confounding factor in the treatment perspective.

    • Andy,
      There are no cattle involved except for the sacrificial ones used to catch the flies. The site is in a protected are with no human agriculture. The paper states that:
      “Each collection team comprised two hand net catchers and an ox, operating within 2 km of the research station. Each team operated at least 200 m from other teams, in areas chosen to maximise catches in accord with seasonal changes in the distribution of tsetse between vegetation types”

      Or in other words the study was designed to specifically overcome the objections you mention. Again you need to read the paper before trying to criticise it.

    • Since the sources of error are not constant, any trend spotted has as much chance of being spurious as it does being real.

  13. When money for grants is the object of the study, there are no un-malleable facts, no un-tamperable graphs or data, no limit to the addition of metal objects to the research equipment or re-siting to increase warming, to be ruled out and no cause to be examined other than Global Warming / Climate Change, so that the desired outcome is achieved.

  14. In figure 1a, something happened to the data series, a shift up around 1983, especially the minima.
    Maybe they added the cattle fencing?

  15. Apparently, the study is based on “recordings [made at] at 7:00 AM each day from maximum and minimum mercury thermometers housed in a Stevenson screen., as noted in the PLOS Medicine paperhere.

    It addition to the problems that Anthony so ably pointed out, it is also known that perfectly sited and maintained Stevenson screens with PRT sensors (precision ±0.1 C) produce a systematic (i.e., non-normal) temperature measurement errors of about ±0.45 C. [1] The LiG thermometers are likely to be less accurate than the PRT, because they’d have a resolution of, at best, ±0.25 C.

    So, even under ideal circumstances, the 57 years of temperature measurements are reportable to only ±0.51 C.

    Then they calculated anomalies from the temperature series mean. Taking differences requires combining errors as the root-mean-square. So, the anomalies are good only to an average 1-sigma uncertainty ±0.73 C.

    The paper says that their, “analyses indicate an increase of c. 0.9°C from the peak in 1975 to the peak in 2017 (Fig 1B). This increase is not even across the year, being greatest in November when temperatures are already highest. During this month, mean daily temperatures increased by c. 2°C between 1975 and 2017 (Fig 2).

    Notice, they provide no uncertainty intervals on their reported temperature (typical for climate science). Well, here’s a minimum uncertainty to apply if *every*single*thing* about the site was ideal.Average increase, 0.9 ±0.73 C, and November increase 2 ±0.73 C, and that’s one sigma. Two sigma (95% confidence) is 0.9 ±1.46 C and 2 ±1.46 C.

    There’s a whoop-de-do important result for everyone. And those uncertainties are apart from the ±5 C that Anthony revealed from his analysis showing the Rekomitjie site is no better than class 5.

    [1] see Hubbard and Lin “Realtime data filtering models for air temperature measurements” GRL 29(10), 67(1-4) here: https://doi.org/10.1029/2001GL013191

  16. From the paper—-
    “We therefore assume a linear increase in larviposition rate with temperature using the equation…” .

    “Tsetses tend to disappear with the encroachment of civilization….” From Chandler, Introduction to Parasitology, 8th edition, 1949. He talks about climate and domestic animal infections and the pupae even have their own parasite. Parasitologists used to be good ecologists, among other things, because parasites are at least as important as predators, and much more difficult to study. I knew a couple that studied under Chandler. They wouldn’t like papers like this, he made them get their hands dirty and once formally described an unnamed fish with a parasite he was studying. Versatility!

    Coincidentally, I just got a journal today whose lead paper was a review on the oyster parasite that decimated the industry in Chesapeake Bay almost six decades ago. Long story, but they don’t know the life cycle, and it may have an intermediate host (like tsetse flies are) that has not been searched for, except for some DNA work, since the 1960s. I heard someone interested had trouble getting funding. Odd thing is all the “ecosystem” and “oyster restoration ” studies done in Chesapeake Bay.

    The few old school parasitologists I have known, among others and myself, worry what could happen. My son once caught malaria, doctor in Austin didn’t recognize it.

  17. Interesting… As long as they did not change the site, the temperature may be biased but the amount of change should not be… unless the equipment is aging and that is affecting the measurements.

    I googled a bit further out and noticed this site is close to a stream or river…whatever they call a mostly dry stream bed in that location. Funny thing is, the resolution of the stream bed is much better both north and south of the site, but near the site it looks very…muddled? I wonder if that is water sitting near the site? If so, the presence of evaporating water near the site could also cause some cooling and impact measurements. If the site is getting dryer, I would expect the temperature to be going up, even if its ground moisture and not necessarily water you can see.

    My understanding of tsetse flies (and it isn’t enormous) is that they are present where cattle range. Less suitable animals about, less tsetse files. This seems far more likely than changing temperatures which might or might not be area wide. One measurement site does not make for a very good baseline.

  18. Read the first few paragraphs and suspected the insecticides were a big factor, even before getting to Anthony’s discussion. Since the 1990s, the ivermectins and related insecticides have dropped to about 10% of their original price in Canada. They kill most intestinal worms, lice and biteing flies. There common usage has practically eliminated the cattle bot, Hypoderma bovis from Eastern North America.

  19. Metal roofing on a weather station – LOL. Biologists wanting to survey reptiles often scatter off cuts of metal roofing around, as they heat up in the sun and provide shelter – hence attracting the critters to lay underneath.

    Great way to turn a weather station into an oven.

  20. Given the reality on the ground in Zimbabwe, you have to spend a long time thinking about the valdity of any data that comes out of it .

  21. The hotter it gets here in Oz especially the outback the more flies appear so the tsetse must be wimps .
    Wish I could post a photo of a Stevenson screen with rocks on the top , no idea why they were there

    • Stevenson screen with rocks on the top , no idea why they were there

      Somebody pointed out that the Stevenson-screen siting was as stupid as a box of rocks, so someone wanted to set it up properly.

  22. Notice anything odd? I sure did.

    Yup, I did:

    Looking at the 1st photo of the weather stations location, I see three (3) more potential problems that will surely bias temperature measurements.

    #1 – the stonework circling the station.

    #2 – all of the bare ground surrounding the station.

    #3 – all of the reflective “white” buildings in close proximity to the station.

  23. I agree with Anthony this is a weird paper. Its biggest weakness, as Anthony points out in his update, is that the temperatures recorded at the station do not reflect the microclimates where the tse rests, feeds and deposits its larvae. I have measured miro-climate temperatures in the Sierra that are 30C cooler within the shrubbery and trees compared to a gravel area just 70 meters away. The tse’s microclimate in the bush is like lower and completely in the safe zone

    I suspect the real dynamic causing less tse, is changes in large mammals that tse must eed on. Large mammal populations seasonally increased in the river valley during the dry season and retreated in the wet season. However It is frequently reported that the construction of the Kariba Dam dried the river bottoms up which has likely reduced the mammals the tse feeds on. A seasonal reduction in large mammals would be enough to cause a cascade of plummeting local tse populations

    Furthermore, poaching has become an increasing problem in the region. The 500 black rhinos were nearly hunted to extinction and the last few were removed to protect them. High poaching pressure likely shifts the center of mammal densities away and again the tse population would be greatly reduced or simply shifted its range elsewhere with higher mammal populations.

    I see this paper as another example of the “Trenberth Fallout” that has denigrated climate science. Trenberth encouraged reversing the null hypothesis, so that no one needs to demonstrate a global warming effect. Trenberth created a “scientific culture” that simply assumes all changes can be at least in part be blamed a global warming. No critical thinking required. Blaming climate change almost guarantees publication no matter how sketch the analyses

  24. “I don’t particularly blame the authors or the reviewers for not noticing this problem, because they aren’t climatologists or meteorologists they are doctors and entomologists, who wouldn’t even know to look for these sorts of problems.”

    In that case they should stick to what they know and butt out of comments on climate unless they consult with a climate specialist. How would they like an Arts researcher to publish profound observations of death rates in hospitals due to clinical error ?

  25. No one is going to mourn for the tse-tse fly, but the attribution seems odd. Unless high temperatures eradicated the fly completely, why wouldn’t the population bounce back when the temperature dropped? According to the article the flies have no increased mortality at all between 20-30C, and the temperature sequence shows that they spend most of their time there — the anomaly increase in pretty much every month except November should be a non-factor.

    And then there’s November. We see occasional incursions above 30C that eventually become annual excursions. But the actual fly data in figure 4 shows a dramatic decrease in the 90s (somewhat obscured by the scale), fairly constant flies in the 2000s, and then 2012-2017 collapses into near-extinction. Looking at the temperatures in figure 1, I’m not seeing a clear alignment between the tiny year-to-year differences and the dramatic differences in figure 4. In their impact charts, the highest temperature daily adult mortality recorded was just over 0.06 at 32.5C and daily pupal mortality just over 0.03 at 32C. Given the short lifespans involved, that seems way too low to account for a population collapse to me, especially since the November mean only crossed 32C once.

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